Libgutenberg

- added a session management decorator to DBUtils so that functions that get a new session also close them. Rebuilds were failing after 75 books.

- fixed missing log method
- fixed import failures when psycopg2 not present
- skip more tests when psycopg2 not present

- change xhtml/RDFa style meta elements in dc.to_html()min to of HTML5 style meta elements.
- change psycopg2 WARNING to an INFO
- deleted redundant log handler. Log messages were printing twice
- set encoding for python files to UTF8; this was causing an encoding error in data sent to db.
- fixed bug in is_same_path

- fix formatting of MARC attributes. Previously the marc formatter assumed a word boundary after the subfield indicator, but that's not aligned with the rest of the world. We have a few attribute fields with dollar amounts, but in every case the char after the $ is a digit. also means [space] in the MARC docs. Ignore that $ means \1F in MARC docs, we'll just use $, until we make real MARC files.

- don't skip zip files
- remove debugging statements
- cache the filetypes and compressions loaded from db
- improved test cleanup

- fixed problem with guess_encoding. In reproducing the regexes I didn't realize that re.match != php's regexp match.
- the handling of updatemode was backwards. While correcting this, I made the logic in save() much clearer